Potentially toxic trace elements in bee bread, propolis, beeswax and royal jelly - A review of the literature and dietary risk assessment.

Scientific evidence suggests that apicultural products accumulate pollutants present in the hive environment, thus, they can be used as bioindicators. However, our understanding on the food safety implications of the presence of potentially toxic trace elements in these products remains incomplete. In our study, available data on the trace metal content of bee bread, propolis, beeswax and royal jelly, as well as their possible sources are reviewed. Furthermore, dietary risk assessments were conducted for elements that do not have any biological role in humans by comparing the estimated exposures with official reference values. In the case of elements with genotoxic carcinogen potential, the margin of exposure (MoE) approach was applied. The observed concentration ranges vary over a wide range for Fe (0.94-2125.20 mg/kg), Zn (

Pesticide residues in bee bread, propolis, beeswax and royal jelly - A review of the literature and dietary risk assessment.

Due to pollinator decline observed worldwide, many studies have been conducted on the pesticide residue content of apicultural products including bee bread, propolis, beeswax and royal jelly. These products are consumed for their nutraceutical properties, although, little information is available on the human health risk posed by pesticides present in them. In our research, studies dealing with the pesticide contamination of the above-mentioned hive products are reviewed. Dietary exposures were calculated based on the recommended daily intake values and concentration data reported by scientific studies. Potential acute and chronic health risk of consumers were evaluated by comparing the exposure values with health-based guidance values. Available data indicate that a wide range of pesticide residues, especially acaricides may accumulate in bee bread, propolis and beeswax, up to concentration levels of more thousand µg/kg. Based on our observations, tau-fluvalinate, coumaphos, chlorfenvinphos, chlorpyrifos and amitraz are commonly detected pesticide active substances in beehive products. Our estimates suggest that coumaphos and chlorfenvinphos can accumulate in beeswax to an extent that pose a potential health risk to the consumers of comb honey. However, it appears that pesticide residues do not transfer to royal jelly, presumably due to the filtering activity of nurse bees during secretion.

Hydrolysis of Soybean Milk Protein by Papain: Antioxidant, Anti-Angiotensin, Antigenic and Digestibility Perspectives.

The objective of the investigation was to understand the biochemical activities of hydrolysate of soybean milk protein (SMP). Hydrolysis was carried out by different concentrations of papain (0.008 g·L-1, 0.016 g·L-1, 0.032 g·L-1 and 0.064 g·L-1). The antioxidant capacity was measured by the ferric-reducing ability of plasma (FRAP) and 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assays. The anti-angiotensin activity of hydrolysate was measured by the recombinant angiotensin converting enzyme and substrate Abz-FRK(Dnp)-P. The contributions of the Kunitz trypsin inhibitor (KTI) and Bowman-Birk inhibitor (BBI) on antigenicity, and the in vitro digestion of papain-hydrolyzed SMP were studied. Rabbit polyclonal anti-KTI and anti-BBI antibodies together with peroxidase-labelled goat anti-Rb IgG secondary antibody were used to identify the antigenicity of KTI and BBI in unhydrolyzed and papain-hydrolyzed SMP. The antioxidant capacity and anti-angiotensin activity of SMP were increased after the papain hydrolysis of SMP. The KTI- and BBI-specific antigenicity were reduced in SMP by increasing the concentration of papain. However, there was interaction between papain-hydrolyzed SMP and trypsin in native gel, while interaction with chymotrypsin was absent. The interaction between trypsin and SMP was reduced due to the hydrolysis of papain in a concentration-dependent manner. According to the in vitro gastrointestinal digestion simulation protocol (Infogest), the digestibility of SMP was not statistically increased.

Application of Near-Infrared Spectroscopy to Investigate Some Endogenic Properties of Pleurotus ostreatus Cultivars.

Fourteen different Pleurotus ostreatus cultivars (Po_1-Po_14) were tested for free amino acid content (fAA), total polyphenol content (TPC), and antioxidant capacity (Ferric Reducing Ability of Plasma-FRAP) to select the cultivars with the most favorable traits. Automatic amino acid analyzer (fAA) and spectrophotometric assay (TPC, FRAP) results as well as Fourier-transform near infrared (FT-NIR) spectra were evaluated with different chemometric methods (Kruskal-Wallis test, Principal Component Analysis-PCA, Linear Discriminant Analysis-LDA). Based on total free amino acid concentrations and FRAP values, the Po_2 cultivar was found to be the most favorable. Types Po_3, Po_8, Po_10 and Po_12 were separated using PCA. Based on the spectral profile, they may contain polyphenols and reducing compounds of different qualities. LDA classification that was based on the concentrations of all free amino acids, cysteine, and proline of the cultivars was performed with an accuracy of over 90%. LDA classification that was based on the TPC and FRAP values was performed with an accuracy of over 83%.

Antioxidant and Antibacterial Peptides from Soybean Milk through Enzymatic- and Membrane-Based Technologies.

Enzymatic hydrolysis of soybean milk proteins with cysteine protease papain was performed in an advanced bioreactor, operated with batch mode. In soybean milk protein hydrolysis reaction, enzyme and substrate ratio and reaction temperature were varied, ranging from 0.029:100-0.457:100 and 30-60 °C, respectively. The degree of hydrolysis of soybean milk proteins was increased with increase of enzyme and substrate (soybean milk protein) ratio. However, the degree of hydrolysis was increased due to change of reaction temperature from 30 °C to 60 °C with enzyme and substrate ratio 0.229:100 and was reduced when hydrolysis reaction was performed with enzyme and substrate ratio 0.11:100 at hydrolysis temperature 60 °C. Antioxidant capacity of enzyme-treated milk had a similar trend with degree of hydrolysis. In a later exercise, a membrane bioreactor was adopted for continuous production of antioxidant and antibacterial peptides from soybean milk. The membrane bioreactor was operated for 12 h with constant feeding. Ceramic-made tubular membrane with a pore size 20 nm was used. Application of static turbulence promoter in a membrane separation process was investigated and its positive effects, with respect to higher permeate flux and lower energy consumption in filtration process, were proven. Antioxidant capacity and antibacterial activity against Bacillus cereus of enzyme-hydrolyzed milk and permeate from membrane were confirmed.

Redox regulation of free amino acid levels in Arabidopsis thaliana.

Abiotic stresses induce oxidative stress, which modifies the level of several metabolites including amino acids. The redox control of free amino acid profile was monitored in wild-type and ascorbate or glutathione deficient mutant Arabidopsis thaliana plants before and after hydroponic treatment with various redox agents. Both mutations and treatments modified the size and redox state of the ascorbate (AsA) and/or glutathione (GSH) pools. The total free amino acid content was increased by AsA, GSH and H2 O2 in all three genotypes and a very large (threefold) increase was observed in the GSH-deficient pad2-1 mutant after GSH treatment compared with the untreated wild-type plants. Addition of GSH reduced the ratio of amino acids belonging to the glutamate family on a large scale and increased the relative amount of non-proteinogenic amino acids. The latter change was because of the large increase in the content of alpha-aminoadipate, an inhibitor of glutamatic acid (Glu) transport. Most of the treatments increased the proline (Pro) content, which effect was due to the activation of genes involved in Pro synthesis. Although all studied redox compounds influenced the amount of free amino acids and a mostly positive, very close (r > 0.9) correlation exists between these parameters, a special regulatory role of GSH could be presumed due to its more powerful effect. This may originate from the thiol/disulphide conversion or (de)glutathionylation of enzymes participating in the amino acid metabolism.